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TSS Calculation

PinaPina
in Racing Forum 🏎

 I understand how TSS is calculated but I have 1 question.

Does TSS have a linear or logarithm calculation? Let me elaborate. I'm racing IMFL next week and if we made several large assumptions such as keeping NP the same and VI very close to 1.00 for the 112 miles. Would it be accurate or inaccurate to assume that if TSS at mile 56 was 130, would TSS at mile 112 be 260?  

Comments

  • Tom GlynnTom Glynn
    TSS is time multiplied by IF squared so as long as your IF is consistent for first and second halves, you should be fairly good. If there is a large discrepancy in the course profile, it may be a little problematic. For example if the first 56 miles were flat and the second where all at a 10 percent grade, it would take a lot longer to finish the second half, thereby increasing your TSS.
  • PinaPina
    Thank you Tom! THis is what I thought, but just wanted to confirm that there was nothing else in the TSS equation.
  • ebe4zippyebe4zippy
    I think Tom is corect on this, but in a pure performance sense, it is not uncommon to see a small decrease in power over the 2nd loop of most courses. EN's JRA start to the race usually evens this out. If you ride steady from T-1, you are putting at risk what you gain from that first part of the bike EN style.
  • Al TruscottAl Truscott
    Posted By Ebe Boettcher on 27 Oct 2012 10:12 AM

    I think Tom is corect on this, but in a pure performance sense, it is not uncommon to see a small decrease in power over the 2nd loop of most courses...



    If you have done the prescribed training for twelve weeks before an IM, power drops in the last 2 hours of an IM bike are a mental focus thing, not a lack of physical fitness, either muscular or cardiac.

  • Tom GlynnTom Glynn
    From a presentation I gave a while ago, a quick primer on all the power jargon.

    Power (measured in watts): RPM x Force = Power, is what you see on the display as watts. This is a real time measurement of the work you performing right now.

    Average Power – power output divided by time

    Normalized Power – complicated formula that provides a better measure of the physiological demands of the work done. Example, ride for one hour @ 150 watts is different than riding at 100 watts for 30 minutes and 30 minutes at 200 watts.

    Functional Threshold - exercise intensity at which lactate begins to accumulate in a person's blood - that is, their lactate threshold (LT) - is a powerful predictor of their endurance performance ability.

    Often measured as the amount of power you can generate in an all out one our ride. The cool thing about the number is that is the best predictor of performance out there and it is highly trainable.


    Intensity Factor (IF) is simply the ratio of the normalized power to your threshold power. For example, if your normalized power for a training ride is 210 W and your threshold power at the time is 280 W, then the IF for that workout would be 0.75.

    Variability Index (VI) is NP/AP – How smooth your riding is.

    Training Stress Score (TSS) – Measures fatigue (Time x IF ^2 x 100)

    One hour at threshold equals 100 TSS points
    One hour at 50% of threshold equals 25 TSS points

    The following scale can be used as an approximate guide:
    • Less than 150 - low (recovery generally complete by following day)
    • 150-300 - medium (some residual fatigue may be present the next day, but gone by 2nd day)
    • 300-450 - high (some residual fatigue may be present even after 2 days)
    • Greater than 450 - very high (residual fatigue lasting several days likely)
    As well, the cumulative TSS per week or per month can be used help identify the maximum intensity and volume of training that still leads to improvements, rather than overtraining.
  • PinaPina
    @Al, caffeine is my best friend 3 hours into 112 miles, hopefully I can minimize a loss of mental focus with that. Thx!

    @Tom, wonderful elaboration. Love to better understand how to calculate a weekly TSS that leads to continued improvements vs. overtraining. Are there more resources expanding on this. Thanks again!
  • William JenksWilliam Jenks
    The trouble with pushingTSS measurements too hard is that they fail at the extremes. It's just a mathematical model. It works great, BUT... When you start reading things like "All TSS points are not created equal..." you should translate that in your head as "The TSS model fails when you are comparing these two things...." because if the TSS model actually was perfect, all TSS points WOULD BE created equal. :-)

    But to answer you original question....linear with time, and exponential with intensity.
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